STUDY OF THE PROGRAMMABLE ISOKINETIC SAMPLER EFFICIENCY FOR OF ECOLOGICAL DIAGNOSTICS SYSTEMS OF HEAT ENGINES AND BOILER PLANTS

Abstract

The work is devoted to the solution of the actual scientific and practical task of creating a universal sampling device for systems of environmental diagnostics of heat engines and boiler plants of various purposes. Ensuring the isokinetic mode of sampling from the exhaust pipe (EP) of the engine is a more difficult task than carrying out a similar sampling process in the chimney of the boiler plant, since the exhaust gases of the engines are characterized by fluctuations of static pressures in the HT with an amplitude of up to ±500 Pa, which must be taken into account in the operation of the sampling equipment. In the course of research, based on the analysis of global and domestic experience in the production and use of equipment for environmental certification of internal combustion engines and boiler houses, a programmable isokinetic sampler (ICT) was created, which allows you to take a proportional part of the gas sample from the full flow of exhaust gases in the EP of the power plant with accuracy ±3%. Motorless and motorized test stands have been developed for modeling and research of gas-dynamic processes in the exhaust systems of engines and boiler plants, which provide the possibility of varying the parameters of gas flows - mass flow rate, speed, temperature, static pressure, velocity pressure in the ranges: 15 - 55 g/s; 5...30 m/s, 20...180 °С, 0...2.5 kPa, 10 - 550 Pa, respectively. On the basis of the created test stands, empirical dependences were established to determine the static pressure differences between the ICP and EP pipelines, in which the isokinetic mode of sampling is ensured, from the dynamic pressure of the gas flow in the EP. With the help of these dependencies, SMART control of the programmable ICP is carried out. An experimental development of the programmable ICP was carried out as part of the MT-1 minitunnel during environmental tests of the 1СН12/14 diesel engine in separate modes and according to the ESC cycle established by the UNECE Regulations R-49. The research results confirmed the compliance of the created sampling device with regulatory requirements for its design and the accuracy of determining the sampling coefficient.